Method of bleaching fibers of vegetable origin



Patented Sept. 30, 1941 UNITED STATES PATENT OFFICE METHOD OF BLEACHING FIBERS OF VEGETABLE ORIGIN Hans 0. Kauifmann, Eggertsville, N. Y., assignor No Drawing.

Application May 10, 1939,

to Buffalo Electro-Chemical Company, Inc.,

Serial No. 272,913

8 Claims.

The present invention relates to a method of treating fibers of vegetable origin for bleaching the same and producing high absorbency of the fibers for liquids.

Heretofore it has become a practice in the textile industry to increase the absorbency of fibers of vegetable origin for liquids by subjecting the fibers to a strongly alkaline solution at elevated temperatures, preferably at or above the boiling point of the solution. In certain cases it has been found necessary to employ a plurality of such treatments to obtain a satisfactory absorbency. Irrespective of the method of bleaching or the bleaching agent employed, whether hypochlorite or peroxide, the fibers require prolonged treatment at elevated temperature with caustic alkali solution to make them absorbent.

Once absorbent properties were imparted to the fibers, subsequent bleaching treatments simply bleached out the natural coloring matter or rendered them colorless and had no bearing upon the absorbency.

Treatment of fibers of vegetable origin with hot circulating caustic soda solutions removes waxes, fats, and other impurities which were present in the fibers prior to, or which were acquired during, or subsequent to, textile processing. The result of such alkaline treatment always decreases the weight of the goods and adversely affects their tensile strength, rendering them harsh and stiff.

Where the goods fabricated from fibers of vegetable origin contain colored dyed portions, it is impossible to subject them to the strong caustic treatment described as the colors will bleed or wash off and in such instances several treatments with relatively mild alkali are required with intermediate bleaching treatments to obtain the desired bleach and absorbency. Such a process requires considerable handling of the goods over an extended period of time; in addition, extra equipment, floor space and washing and rinsing facilities are necessarily required.

However, white and colored yarn may be bleached with peroxides fiiciently and expeditiously in one treatment without the necessity of the preliminary caustic treatment by subjecting such goods to a weakly alkaline peroxide solution for several hours at elevated temperatures; goods produced in this manner, although of excellent white and quality, lack absorbency. If such goods are to be subsequently dyed, they must be treated before the dyeing operation in special ways in order to produce the necessary absorbency for receiving the dyestuif properly;

even with such a treatment the goods ar not perfect as they possess merely a surface absorbency rather than a body absorbency.

It has also been suggested to increase the absorbency of fibers of vegetable origin and of goods made therefrom, by treating the same with certain oily materials which possess the specific property of increasing the absorbency of the fiber. Absorbency induced by this method, however, is not of a permanent nature and disappears upon heating or storing the goods and in many instances due to subsequent treatments thereof. In order to again obtain the absorbency desired, the goods have to be again treated with the oily material.

It is an object of the present invention to provid a method for increasing the absorbency of fibers of vegetable origin.

It is also an object of the present invention to provide a method for simultaneously bleaching and making fibers of vegetable origin readily absorbent and easily wettable.

It is a still further object of the present invention to provide a means for simultaneously bleaching and increasing the absorbency of fibers in periods of time much shorter than have been required heretofore to attain this same result.

It is also an object of the invention to produce absorbency in fibers of vegetable origin that is substantially permanent and not destroyed by subsequent treatments of the goods.

Other objects and advantages will be described more fully hereinafter and pointed out with particularity in the claims.

In accordance with the procedure of the present invention, the goods to be treated, Whether raw fibers, yarns, woven or knitted goods, and whether the same be of natural gray goods or of artificial fibers, or of both artificial and natural fibers, are wetted with an alkaline bleaching solution containing a peroxide or percompound and a water soluble surface tension reducing agent and subjected to heat without addition of additional bleaching solution and while maintaining the goods damp. In general, the goods, dampened with the bleaching and. absorbency inducing agents, are subjected to the action of these materials at a temperature of from about 160 to 220 F. for a period of time suificient to bleach the goods.

The bleaching solution is formulated from the percompounds, as, for instance, hydrogen peroxide, alkali and alkaline earth metal peroxides, metal peroxides, perborates, percarbonates, persilicates, and the like, all of which in solution generate a peroxide. The quantity of percompound to be added to the solution depends upon the type of fiber to be bleached and the degree of bleaching desired. In general, the bleaching solution will contain the equivalent of from about 0.1% to 3% hydrogen peroxide, 100-volume.

The bleaching solution for best results should contain alkali, in addition to the surface tension reducing agent, that is the ingredient increasing absorbency. The preferred alkalis are caustic soda, sodium silicate, sodium pyrophosphate, ammonia, soda ash, or other well-known alkalies. In general the concentration of alkali will be dictated by the type of goods treated, gray goods requiring more alkali than goods that have been preliminarily treated. In general about 2 to 50 grams per liter of alkali, calculated as sodium hydroxide, will be effective, although about to grams per liter of NaOH will be sufficient for most goods.

The quantity of bleaching solution with which the fibers are wetted is about 50 to 150% of the weight of the dry fibers. Dampening or wetting is effected generally by immersing the goods in the bleaching solution and so soon as the goods are wetted, expressing the excess of the solution by means of squeezer rolls or by hydroextracting in a centrifuge or by any other convenient method.

After the goods are squeezed and consequently in a damp condition, they are subjected to heat. Generally the goods are heated for from about two minutes to several hours, or until the desired degree of bleaching is obtained. The heating should be carried out in such fashion as to prevent them from drying out since they should contain some solution at the end of the heating period. The temperature employed will depend upon the type of fiber treated and the degree of bleaching desired. Generally the temperature will be between about 160 F. to about 230 F. The goods may be heated, for instance, by exposing them to the direct action of steam.

The method of the present invention finds widest application in the treatment of cotton goods, although applicable to artificial fibers and fibers of vegetable origin generally. By increasing the alkali content, excellent results, both as to degree of bleaching and the absorbing qualities of the goods, are increased, and it is possible to treat gray goods with removal of motes and shives without damaging the goods.

The absorbency of the fiber is produced by adding to the bleaching solution a surface tension reducing agent. Suitable surface tension reducing agents are the soluble salts of the higher fatty acids, such as oleate and stearate soaps, i. e., the alkali metal salts of the fatty acids, including ammonium salts, sulfonates and sulfates of fatty acids, alcohols, esters and related substances. soluble pine oil, Turkey red oil, and the like. These materials are added in quantities of about 1 to 20 grams per liter of solution although quantities greater or lower than this may be employed.

The absorbency of the fiber is determined by placing a small sample of the fiber upon the surface of distilled water and the time required for the fiber to wet out and sink below the surface determined.

The following are specific examples purely illustrative of the principles of the invention but not limitative thereof.

A sample of y on goods was immersed in a bleaching solution of Composition A, the excess squeezed out to a liquor ratio of 1:1 so that the goods contained, bleaching solution on the Weight of dry fiber and the fiber then steamed at 212 F. for nine minutes. The steamed goods were rinsed with water, hydroextracted and ironed. The material did not wet out in twenty minutes.

Composition A in 1000 cc.

NaOH g 15 Sodium silicate (40-42 B.) cc 40 100-volume hydrogen peroxide cc 40 Blank minutes Over 20 Oleate soap, 12.5 g ..seconds.. it Tallow soap, 15 g (10.... it Turkey-red oil, 10 cc.-. do as Soluble pine oil, 10 cc do 1 Sulfonated mineral oil, 5 cc. do.... 2% Igepon (amino ethane sulfate of fatty acid), 5 g -;do.- 3 Aerosol (sulfonated ester of dicarboxylic acid), 5 g do 2 Nacconol (alkyl aryl sulfonate), 5 g .do. 3% Gardinol (sulfate of fatty alcohol), 5 g do 4 It will be understood that the composition given above is purely illustrative of the principles of the invention and is not considered limitative as the composition can be varied widely.

In general, caustic soda will be employed as the alkali with hydrogen peroxide; however, other alkalis may be employed and substances generating hydrogen peroxide substituted therefor.

The amount of hydrogen peroxide employed will be dictated by the type of goods being bleached and by the degree of white desired. In general, about 5 to 100 cc. of 100-volume hydrogen peroxide will be added for each liter of the bleaching solution with about 25 to 45 cc. being the preferred range for gray goods.

From the foregoing it will be seen that the present invention provides a method for bleaching goods and at the same time producing goods of high absorbency, the whole procedure requiring but a short period of time even when the goods treated are in the gray condition.

I claim:

1. The method of treating fibers of vegetable origin in the gray state, which comprises impregnating the fiber with less than about of an alkaline bleaching solution comprising a percompound and a soap based on the weight of the fiber and subjecting the so impregnated fiber to heat while preventing any substantial evaporation therefrom.

2. The method of treating fibers of vegetable origin in the gray state which comprises impregnating the fiber with less than about 150% of an alkaline bleaching solution comprising a percompound and pine oil based on the weight of the fiber and subjecting the so impregnated fiber to heat while preventing any substantial evaporation therefrom.

3. The method of treating fibers of vegetable origin in the gray state which comprises impregnating the fiber with less than about 150% of an alkaline bleaching solution comprising a percompound and Turkeyred oil based on the weight it'z'lllil? of the fiber and subjecting the so impregnated fiber to heat while preventing any substantial evaporation therefrom.

4. The method of treating fibers of vegetable origin in the gray state, which comprises impregnating the fiber with less than about 150% of an alkaline bleaching solution comprising a percompound and a surface tension reducing agent based on the weight of the fiber and subjecting the so impregnated fiber to heat while preventing any substantial evaporation therefrom.

5. The method of treating fibers of vegetable origin in the gray state, which comprises impregnating the fiber with less than about 150% of an alkaline bleaching solution comprising a percompound and a surface tension reducing agent based on the weight of the fiber and thereafter steaming the so impregnated fiber until they are bleached and are absorbent.

6. The method of treating fibers of vegetable origin in the gray state, which comprises immersing the fiber in an alkaline bleaching solution comprising a percompound and a surface tension reducing agent, removing the excess of solution above that required to dampen the fiber and thereafter heating the fiber while preventing any substantial evaporation therefrom.

'7. The method of treating fibers of vegetable origin in the gray state, which comprises immersing the fiber in an alkaline bleaching solution comprising a percompound and a surface tension reducing agent, expressing the excess of solution above that required to dampen the fiber and thereafter steaming the fiber until they are bleached and are absorbent.

8. The method of bleaching gray goods made of fibers of vegetable origin, which comprises impregnating the fiber with less than about 150% of an alkaline bleaching solution comprising a percompound and a surface tension reducing agent based on the weight of the fiber and thereafter steaming the so impregnated fiber.

HANS O. KAUFFMANN. 

